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1.
Environ Res ; 245: 117998, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38145735

RESUMO

The present work demonstrates a novel strategy of synthesizing iron-biochar (Fe@BCSB) composite made with the waste iron bottle cap and sugar cane bagasse for implementation in the three-dimensional electro-Fenton (3DEF) process. The catalytic ability of the Fe@BCSB composite was explored to remediate the sodium dodecyl sulphate (SDS) surfactant from wastewater at neutral pH. At the optimum operating condition of Fe@BCSB dose of 1.0 g L-1, current density of 4.66 mA cm-2, and Na2SO4 dose of 50 mM, nearly 92.7 ± 3.1% of 20 mg L-1 of SDS abatement was attained during 120 min of electrolysis time. Moreover, the Fe@BCSB showed significant recyclability up to six cycles. Besides, other organics were successfully treated with more than 85% abatement efficiency in the proposed Fe@BCSB-supported 3DEF process. The total operating cost obtained during SDS treatment was around 0.31 US$ m-3 of wastewater. The phytotoxicity test revealed the positive impact of the 3DEF-treated effluent on the germination of the Vigna radiata. The electron paramagnetic resonance conveyed •OH as the prevailing reactive species for the oxidation of SDS in the 3DEF process. Further, about 81.3 ± 3.8% of SDS and 53.7 ± 4.1% of mineralization efficacy were acquired from the real institutional sewage.


Assuntos
Carvão Vegetal , Saccharum , Poluentes Químicos da Água , Ferro , Águas Residuárias , Celulose , Dodecilsulfato de Sódio , Eletrodos , Peróxido de Hidrogênio , Oxirredução , Poluentes Químicos da Água/análise
2.
Environ Res ; 262(Pt 1): 119821, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39173817

RESUMO

The industrial production of synthetic fertilizers and the wide-scale combustion of fossil fuels have disrupted the global nitrogen cycle, necessitating a prudent shift towards sustainable nitrogen management. Traditional wastewater treatment methods primarily focus on nitrogen elimination rather than recovery in useable form, exacerbating resource depletion and environmental degradation. This review explores integrated technologies, including bio-electroconcentration cells (BEC), direct ammonia fuel cells (DAFC), solid oxide fuel cells (SOFC), and microbial fuel cells (MFC), for effective nutrient recovery in conjugation with energy recovery. Recovered nitrogen, primarily green ammonia, offers a carbon-free energy carrier for diverse applications, including applications in DAFC and SOFC. This review underscores the importance of synchronously retrieving ammonia from wastewater and efficiently diverting it for energy recovery using an integrated fuel cell approach. The key technical challenges and future perspectives are discussed, highlighting the potential of these integrated systems to advance sustainability and circular economy goals.

3.
J Environ Manage ; 366: 121719, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38981268

RESUMO

Microbial desalination cells (MDCs) are considered as a sustainable technology for water desalination, wastewater treatment, and power generation. However, this neoteric technology suffers from different challenges, including sluggish oxygen reduction reaction and poor electron transfer from microbes to electrodes, ultimately leading to less power generation and desalination efficiency. This review delves into the intricate roles of both abiotic and biocatalysts in enhancing performance of MDCs through ion removal and charge transfer mechanisms. Detailed discussions highlight the comparative advantages and limitations of different catalyst types and insights into electrode modifications to optimise catalytic activity and biofilm formation. Further, recent advancements in electrode engineering, including surface coatings and integration of nanomaterial, geared towards enhancing efficiency of MDC and performance stability are discussed. Finally, future recommendations are provided, focusing on innovative catalyst designs, material integration, and considerations for scale-up and commercialisation, thereby offering a comprehensive roadmap for the continued advancement of MDC.


Assuntos
Eletrodos , Purificação da Água , Purificação da Água/métodos , Catálise , Salinidade , Águas Residuárias/química , Biofilmes , Fontes de Energia Bioelétrica
4.
Water Sci Technol ; 89(4): 859-872, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38423605

RESUMO

A batch-scale electro-Fenton (EF) process was performed using graphite anode and waste battery-based Fe -Mn -Zn/C electrocatalyst coated on low-cost graphite felt cathode. The effectiveness of the EF's performance was evident with around 83.9 + 4.1% removal of 20 mg/L of sodium-dodecyl sulfate surfactant (SDS) at an optimum current density (CD) of 5.0 mA/cm2, Na2SO4 of 0.05 M, initial pH of 7.2, and electrolysis time of 180 min. Moreover, nearly 1.78-fold more removal of SDS was achieved in EF than in the electro-oxidation process operated without any catalyst. The operating cost of 0.35 $ of per m3 per order was needed to treat SDS wastewater. The remediation of SDS follows pseudo-first-order kinetics with a rate constant of 0.0095 min-1. Additionally, 90.3 + 2.1% of SDS and 57 + 2.6% of total organic carbon (TOC) removal was attained during 240 min of treatment time in secondary treated real wastewater; hence, additional 60 min of treatment time is required for effectively treating real wastewater than synthetic wastewater. Thus, EF is effective with battery waste-derived magnetic catalyst for treating wastewater containing SDS, which can lead to achieving sustainable environmental goals.


Assuntos
Grafite , Poluentes Químicos da Água , Águas Residuárias , Dodecilsulfato de Sódio , Tensoativos , Poluentes Químicos da Água/análise , Peróxido de Hidrogênio , Oxirredução , Eletrodos , Fenômenos Magnéticos , Zinco
5.
J Environ Manage ; 332: 117323, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36716542

RESUMO

Microbial electrosynthesis (MES) is a neoteric technology that facilitates biocatalysed synthesis of organic compounds with the aid of homoacetogenic bacteria, while feeding CO2 as an inorganic carbon source. Operating MES with surplus renewable electricity further enhances the sustainability of this innovative bioelectrochemical system (BES). However, several lacunae exist in the domain knowledge, stunting the widespread application of MES. Despite significant progress in this area over the past decade, the product yield efficiency is not on par with other contemporary technologies. This bottleneck can be overcome by adopting a holistic approach, i.e., applying innovative and integrated solutions to ensure a robust MES operation. Further, the widespread deployment of MES exclusively relies on its ability to mature a sessile biofilm over a biocompatible electrode, while offering minimal charge transfer resistance. Additionally, operating MES preferably at H2-generating reduction potential and valorising industrial off-gas as carbon substrate is crucial to accomplish economic sustainability. In light of the aforementioned, this review collates the latest progress in the design and development of MES-centred systems for valorisation of CO2 into value-added products. Specifically, it highlights the significance of inoculum pre-treatment for promoting biocatalytic activity and biofilm growth on the cathodic surface. In addition, it summarizes the diverse materials that are commonly used as electrodes in MES, with an emphasis on the importance of inexpensive, robust, and biocompatible electrode materials for the practical application of MES technology. Further, the review presents insights into media conditions, operational factors, and reactor configurations that affect the overall performance of MES process. Finally, the product range of MES, downstream processing requirements, and integration of MES with other environmental remediation technologies are also discussed.


Assuntos
Dióxido de Carbono , Eletricidade , Dióxido de Carbono/química , Carbono , Reatores Biológicos , Compostos Orgânicos , Eletrodos
6.
J Basic Microbiol ; 62(3-4): 260-278, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35014053

RESUMO

Cytotoxic, mutagenic, and carcinogenic contaminants, such as heavy metals and radionuclides, have become an alarming environmental concern globally, especially for developed and developing nations. Moreover, inefficient prevalent wastewater treatment technologies combined with increased industrial activity and modernization has led to increase in the concentration of toxic metals and radioactive components in the natural water bodies. However, for the improvement of ecosystem of rivers, lakes, and other water sources different physicochemical methods such as membrane filtration, reverse osmosis, activated carbon adsorption, electrocoagulation, and other electrochemical treatment are employed, which are uneconomical and insufficient for the complete abatement of these emerging pollutants. Therefore, the application of bioremediation employing aquatic macrophytes and microphytes have gained considerable importance owing to the benefits of cost-effectiveness, eco-friendly, and higher energy efficiency. Thus, the present review aims to enlighten the readers on the potential application of algae, cyanobacteria, plant, and other aquatic micro- and macrophytes for the elimination of carcinogenic metals and radioactive isotopes from wastewater. Additionally, the use of transgenic plants, genetically modified species, algal-bacterial symbiosis for the enhancement of removal efficiency of mutagenic contaminants are also highlighted. Furthermore, species selection based on robustness, mechanism of different pathways for heavy metal and radionuclide detoxification are elucidated in this review article.


Assuntos
Cianobactérias , Metais Pesados , Microalgas , Poluentes Químicos da Água , Biodegradação Ambiental , Cianobactérias/metabolismo , Ecossistema , Metais Pesados/metabolismo , Microalgas/metabolismo , Radioisótopos , Águas Residuárias , Poluentes Químicos da Água/metabolismo
7.
J Environ Manage ; 316: 115295, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35597211

RESUMO

Advanced oxidation processes (AOPs) are promising technologies for partial or complete mineralization of contaminants of emerging concern by highly reactive hydroxyl, hydroperoxyl, superoxide, and sulphate radicals. Detailed investigations and reviews have been reported for conventional AOP systems that have been installed in full-scale wastewater treatment plants. However, recent efforts have focused on the peroxymonosulphate, persulphate, catalytic ozonation, ultrasonication and hydrodynamic cavitation, gamma radiation, electrochemical oxidation, modified Fenton, and plasma-assisted AOPs. This critical review presents the detailed mechanisms of emerging AOP technologies, their performance for treatment of contaminants of emerging concern, the relative advantages and disadvantages of each technology, and the remaining challenges to scale-up and implementation. Among the evaluated technologies, the modified electrochemical oxidation, gamma radiation, and plasma-assisted systems demonstrated the greatest potential for successful and sustainable implementation in wastewater treatment due to their environmental safety, compatibility, and efficient transformation of contaminants of emerging concern by a variety of reactive species. The other emerging AOP systems were also promising, but additional scale-up trials and a deeper understanding of their reaction kinetics in complex wastewater matrices are necessary to determine the technical and economic feasibility of full-scale processes.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Peróxido de Hidrogênio , Radical Hidroxila , Oxirredução , Águas Residuárias/análise , Poluentes Químicos da Água/análise
8.
J Environ Manage ; 300: 113694, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34537557

RESUMO

In recent years, Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) have surfaced as a novel class of pollutants due to their incomplete degradation in wastewater treatment plants and their inherent ability to promote physiological predicaments in humans even at low doses. The occurrence of the most common NSAIDs (diclofenac, ibuprofen, naproxen, and ketoprofen) in river water, groundwater, finished water samples, WWTPs, and hospital wastewater effluents along with their toxicity effects were reviewed. The typical concentrations of NSAIDs in natural waters were mostly below 1 µg/L, the rivers receiving untreated wastewater discharge have often showed higher concentrations, highlighting the importance of effective wastewater treatment. The critical analysis of potential, pathways and mechanisms of microbial degradation of NSAIDs were also done. Although studies on algal and fungal strains were limited, several bacterial strains were known to degrade NSAIDs. This microbial ability is attributed to hydroxylation by cytochrome P450 because of the decrease in drug concentrations in fungal cultures of Phanerochaete sordida YK-624 on incubation with 1-aminobenzotriazole. Moreover, processes like decarboxylation, dehydrogenation, dechlorination, subsequent oxidation, demethylation, etc. also constitute the degradation pathways. A wide array of enzymes like dehydrogenase, oxidoreductase, dioxygenase, monooxygenase, decarboxylase, and many more are upregulated during the degradation process, which indicates the possibility of their involvement in microbial degradation. Specific hindrances in upscaling the process along with analytical research needs were also identified, and novel investigative approaches for future monitoring studies are proposed.


Assuntos
Preparações Farmacêuticas , Poluentes Químicos da Água , Anti-Inflamatórios não Esteroides , Humanos , Ibuprofeno , Naproxeno/análise , Phanerochaete , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
9.
Appl Microbiol Biotechnol ; 102(22): 9419-9432, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30259099

RESUMO

Conventional wastewater treatment consumes a large amount of money worldwide for removal of pollutants prior to its discharge into water body or facilitating reuse. Decreasing energy expenditure during wastewater treatment and rather recovering some value-added products while treating wastewater is an important goal for researchers. Microbial fuel cells (MFCs) are representative bioelectrochemical systems, which offer energy-efficient wastewater treatment. MFCs convert chemical energy of organic matter into electrical energy by using biocatalytic activities. Although MFCs are not truly commercialized, they have potential to make energy-gaining wastewater treatment technologies and represent their capabilities successfully. Over the last decade, MFCs have developed remarkably in almost every dimension including wastewater treatment capabilities, power output, and cost optimization; however, its architectural design is an important consideration for scaling up. Here, we review various architectural advancements and technology up-gradation MFCs have experienced during its journey, to take this technology step forward for commercialization.


Assuntos
Bactérias/química , Fontes de Energia Bioelétrica/microbiologia , Águas Residuárias/microbiologia , Bactérias/genética , Bactérias/metabolismo , Fontes de Energia Bioelétrica/economia , Fontes de Energia Bioelétrica/tendências , Eletricidade , Águas Residuárias/química , Purificação da Água/economia , Purificação da Água/métodos
10.
Environ Technol ; 36(5-8): 767-75, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25182800

RESUMO

Dual-chamber microbial fuel cells (MFCs), made of clayware cylinder, were operated at different chemical oxygen demands: ammonium-nitrogen (COD:NH4+) ratio (1:1, 10:1 and 5:1) under batch mode for simultaneous removal of ammonia and organic matter from wastewater. Ammonium-N removal efficiencies of 63-32.66% were obtained for COD:NH4+ ratio of 1:10, respectively. Average COD removal efficiencies demonstrated by these MFCs were about 88%; indicating effective use of MFCs for treatment of wastewater containing organic matter and high ammonia concentration. MFCs operated with COD:NH4+ ratio of 10:1 produced highest volumetric power density of 752.88 mW/m3. The ammonium-N removal slightly increased when microbes were exposed to only ammonium as a source of electron when organic source was not supplemented. When this MFC was operated with imposed potential on cathode and without aeration in the cathode chamber, oxidation of ammonium ions at a faster rate confirmed anaerobic oxidation. During the non-turnover condition of cyclic voltammetry, MFC operated with COD:NH4+ ratio of 10:1 gave higher oxidative and reductive currents than MFC operated with COD:NH4+ ratio of 1:1 due to higher redox species. Successful application of such an anammox process for ammonium oxidation in MFCs will be useful for treatment of wastewater containing higher ammonium concentration and harvesting energy in the form of electricity.


Assuntos
Compostos de Amônio/química , Fontes de Energia Bioelétrica , Purificação da Água/métodos , Aerobiose , Estudos de Viabilidade , Nitratos/química , Oxirredução
11.
Chemosphere ; 352: 141392, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38325616

RESUMO

A microbial fuel cell (MFC) is a cutting-edge bioelectrochemical technology, which demonstrates power and other valuables recovery while treating wastewater by cultivating electroactive microbes. However, rampant biofilm growth over the cathode surface of air cathode MFC exacerbates the oxidation-reduction reaction rate, triggering a dip in the overall performance of MFC. In this sense, biosynthesized silver nanoparticles (AgNPs) have garnered a plethora of potential applications as cathode catalysts as well as anti-biofouling agent for MFCs without harming nature. The MFC equipped with the mixture of aloe vera and algae (@5 mg/cm2) synthesized AgNPs on cathode generated a maximum power density of 66.5 mW/m2 and chemical oxygen demand removal efficiency of 85.2%, which was ca. 5.6 times and 1.2 times higher compared to control MFC operated without any catalyst on cathode. Thus, this investigation paves the way for using eco-amiable, low-cost bioderived organic compounds to assist MFC in achieving high power output and other valuables with minimal reliance on chemicals.


Assuntos
Fontes de Energia Bioelétrica , Nanopartículas Metálicas , Prata , Águas Residuárias , Eletrodos , Eletricidade
12.
Bioresour Technol ; 406: 131038, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38925410

RESUMO

Cytotoxic, malignant, and mutagenic pollutants like heavy metals have emerged as a serious global threat to the ecosystem. Additionally, the quantity of noxious metals in water bodies has increased due to expanding industrial activities and the application of incompetent wastewater treatment techniques. Owing to the benefits of eco-friendly phytoremediation, the utilization of algae in photosynthetic microbial fuel cell (PMFC) for removal of heavy metals has attracted increasing attention among researchers. Therefore, a successful fabrication and operation of a modular PMFC for simultaneous algal biomass production was exhibited, thus resulting in significant removal efficiency of Cu(II) (94 %) and Co(II) (88 %). Moreover, Co(II)-accumulated algal biochar after thermal activation was utilized as a cathode catalyst for the first time and attained 64.2 mW/m2 of power density through PMFC. Hence, this easily synthesised green cathode catalyst proved its ability to enhance the overall performance of PMFC by attaining higher power output while treating wastewater.


Assuntos
Fontes de Energia Bioelétrica , Biomassa , Eletrodos , Metais Pesados , Fotossíntese , Catálise , Biodegradação Ambiental , Carvão Vegetal/química , Poluentes Químicos da Água , Águas Residuárias/química , Purificação da Água/métodos
13.
Environ Sci Pollut Res Int ; 31(8): 11349-11370, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38180651

RESUMO

The uncontrolled discharge of industry- and consumer-derived micropollutants and synthetic contaminants into freshwater bodies represents a severe threat to human health and aquatic ecosystem. Inexpensive and highly efficient wastewater treatment methods are, therefore, urgently required to eliminate such non-biodegradable, recalcitrant, and toxic organic pollutants. In this context, advanced oxidation processes, particularly heterogenous photocatalysis, have received enormous attention over the past few decades. Among the different classes of photocatalysts explored by the scientific community, heterojunction photocatalysts, in general, and binary heterojunction photocatalysts, in particular, have shown tremendous promise, attributed to their many distinct advantages. As such, the present review highlights the application of diverse array of binary heterojunction photocatalysts for eliminating water-borne contaminants. Specifically, a bibliometric analysis has been conducted to identify the ongoing research trend and future prospects of heterojunction photocatalysts. It appears that metal oxide/metal oxide-based heterojunctions have superior thermal and mechanical stability compared to other heterojunction photocatalysts. In contrast, metal oxide/non-metal semiconductor-based heterojunctions are extremely effective in pollutant degradation without significant leaching of metal ions. The review concludes by proposing novel strategic research guidelines in order to make further advances in this rapidly evolving cross-disciplinary field of topical interest.


Assuntos
Líquidos Corporais , Poluentes Ambientais , Humanos , Ecossistema , Bibliometria , Óxidos
14.
Bioresour Technol ; 413: 131467, 2024 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-39260730

RESUMO

Wastewater resources can be used to produce microbial protein for animal feed or organic fertiliser, conserving food chain resources. This investigation hasemployed thefermented sewage to photoheterotrophically grown purple non-sulfur bacteria (PNSB) in a 2.5 m3 pilot-scaleraceway-pond with infrared light to produce proteinaceous biomass. Fermented sewage with synthetic media consisting of sodium acetate and propionic acids at a surface-to-volume (S/V) ratio of 10 m2/m3 removed 89%, 93%, and 81% of chemical oxygen demand, ammonium nitrogen, and orthophosphate, respectively; whereas respective removal in fermented sewage alone without synthetic media was 73%, 73%, and 72% during batch operation of 120 h. The biomass yield of 0.88-0.95 g CODbiomass /g CODremoved with protein content of 40.3 ± 0.3%-43.9 ± 0.2% w/w was obtained for fermented sewage with synthetic media. The results revealed enhanced possibility of scaling-up the raceway reactor to recover resources from municipal wastewater and enable simultaneous high-rate PNSB single-cell protein production.

15.
Bioresour Technol ; 389: 129809, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37797801

RESUMO

The mounting threat of global warming, fuelled by industrialization and anthropogenic activities, is undeniable. In 2017, atmospheric carbon dioxide (CO2), the primary greenhouse gas, exceeded 410 ppm for the first time. Shockingly, on April 28, 2023, this figure surged even higher, reaching an alarming 425 ppm. Even though extensive research has been conducted on developing efficient carbon capture and storage technologies, most suffer from high costs, short lifespans, and significant environmental impacts. Recently, the use of engineered nanomaterials (ENM), particularly in microbial electrochemical technologies (METs), has gained momentum owing to their appropriate physicochemical properties and catalytic activity. By implementing ENM, the MET variants like microbial electrosynthesis (MES) and photosynthetic microbial fuel cells (pMFC) can enhance carbon capture efficiency with simultaneous bioenergy production and wastewater treatment. This review provides an overview of ENMs' role in carbon capture within MES and pMFC, highlighting advancements and charting future research directions.


Assuntos
Fontes de Energia Bioelétrica , Gases de Efeito Estufa , Nanoestruturas , Tecnologia , Dióxido de Carbono/química
16.
Environ Sci Pollut Res Int ; 30(44): 98995-99012, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35661302

RESUMO

The emission of CO2 from industrial (24%) and different anthropogenic activities, like transportation (27%), electricity production (25%), and agriculture (11%), can lead to global warming, which in the long term can trigger substantial climate changes. In this regard, CO2 sequestration and wastewater treatment in tandem with bioenergy production through photosynthetic microbial fuel cell (PMFC) is an economical and sustainable intervention to address the problem of global warming and elevating energy demands. Therefore, this review focuses on the application of different PMFC as a bio-refinery approach to produce biofuels and power generation accompanied with the holistic treatment of wastewater. Moreover, CO2 bio-fixation and electron transfer mechanism of different photosynthetic microbiota, and factors affecting the performance of PMFC with technical feasibility and drawbacks are also elucidated in this review. Also, low-cost approaches such as utilization of bio-membrane like coconut shell, microbial growth enhancement by extracellular cell signalling mechanisms, and exploitation of genetically engineered strain towards the commercialization of PMFC are highlighted. Thus, the present review intends to guide the budding researchers in developing more cost-effective and sustainable PMFCs, which could lead towards the commercialization of this inventive technology.


Assuntos
Fontes de Energia Bioelétrica , Águas Residuárias , Sequestro de Carbono , Dióxido de Carbono , Eletricidade , Eletrodos
17.
Environ Pollut ; 322: 121242, 2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36758930

RESUMO

The current research demonstrates the efficiency of a low-cost MIL-53(Fe)-metal-organic framework (MOF) derived Fe3O4@C (MIL-53(Fe)@Fe3O4@C) electrocatalyst in a batch-scale electro-Fenton (EF) process for the degradation of salicylic acid (SA) from wastewater. The electrocatalyst was prepared from the combination of polyethylene terephthalate (PET) and iron scrap wastes. The result showed 91.68 ± 3.61% degradation of 50 mg L-1 of SA under optimum current density of 5.2 mA cm-2, and pH of 7.0 during 180 min of electrolysis time. The degradation of SA from waste catalyst was similar to the chemical-based MIL-53(Fe)-derived Fe3O4@C (cFe) cathode catalyst. The presence of chloride ions (Cl-) in the water matrix has shown a strong inhibitory effect on the elimination of SA, followed by nitrate (NO3-), and bicarbonate (HCO3-) ions. The multiple cyclic voltammetry (CV) analysis and reusability test of waste cathode catalyst showed only 8.03% drop of current density at the end of the 20th cycle and 5% drop of degradation efficiency after 6th cycle with low leaching of iron. The radical scavenging experiment revealed that the HO• generated via electrochemical generation of H2O2 had a prominent contribution in the removal of SA compared to HO2•/O2•-. Besides, possible catalysis mechanism and degradation pathways were deduced. Furthermore, a satisfactory performance in the treatment of SA spiked in real water matrices was also observed by waste-derived Fe3O4@C cathode catalyst (wFe). Additionally, the total operating cost and toxicity analysis showed that the as-synthesized wFe cathode catalyst could be appropriate for removing organic pollutants from wastewater in the large-scale application.


Assuntos
Ferro , Poluentes Químicos da Água , Ferro/análise , Águas Residuárias , Polietilenotereftalatos , Plásticos , Peróxido de Hidrogênio/análise , Ácido Salicílico , Poluentes Químicos da Água/análise , Catálise , Água/análise , Oxirredução , Eletrodos
18.
Sci Total Environ ; 885: 163941, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37149167

RESUMO

Chlorinated paraffins (CPs) involve a wide range of complex mixtures of chlorinated alkanes. The versatility of their physicochemical properties and their wide range of use has turned them into ubiquitous materials. This review covers the scope of remediating CP-contaminated water bodies and soil/sediments via thermal, photolytic, photocatalytic, nanoscale zero-valent iron (NZVI), microbial and plant-based remediation techniques. Thermal treatments above 800 °C can lead to almost 100 % degradation of CPs by forming chlorinated polyaromatic hydrocarbons and thus should be supported with appropriate pollution control measures leading to high operational and maintenance costs. The hydrophobic nature of CPs lowers their water solubility and reduces their subsequent photolytic degradation. However, photocatalysis can have considerably higher degradation efficiency and generates mineralized end products. The NZVI also showed promising CP removal efficiency, especially at lower pH, which is challenging to achieve during field application. CPs can also be bioremediated by introducing both naturally occurring bacteria and also by engineered bacterial strains which are capable of producing specific enzymes (like LinA2 and LinB) to catalyze CP degradation. Depending on the type of CP, bioremediation can even achieve a dechlorination efficiency of >90 %. Moreover, enhanced degradation rates can be achieved through biostimulation. Phytoremediation has also exhibited CP bioaccumulation and transformation tendencies, both at lab-scale and in field-scale studies. The future research scope can include developing more definitive analytical techniques, toxicity and risk assessment studies of CPs and their degradation products, and technoeconomic and environmental assessment of different remediation approaches.


Assuntos
Hidrocarbonetos Clorados , Solo , Parafina/análise , Monitoramento Ambiental/métodos , Hidrocarbonetos Clorados/análise , Biodegradação Ambiental , Água
19.
Environ Technol ; : 1-16, 2023 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-36872877

RESUMO

The present work focused on extracting lactic and acetic acids from the leachate collected from leached bed reactor (LBR) during acidogenesis of food waste using the reactive extraction (RE) process. A wide range of diluents was screened either alone by physical extraction (PE) or in combination with extractants using RE to extract acids from the VFA mix. Aliquat 336-Butyl acetate/MIBK extractants in RE demonstrated higher distribution coefficients (k) and extraction yield (E %) than PE. The response surface methodology (RSM) was used to optimize the extraction of lactic and acetic acids from the synthetic acid mix, using three variables (extractant concentrations, solute/acid concentration and time). Consequently, these three variables were optimized for LBR leachate. The RE was promising, and extraction efficiencies of 65% (lactate), 75% (acetate), 86.2% (propionate) and almost 100% for butyrate and medium-chain fatty acids (MCFA) were achieved after 16 h of extraction. The RSM optimization predicted a maximum E % of 59.60% and 34.67% for lactate and acetate in 5.5 and 1.17 min, respectively. In the leachate experiment, an increase in E% and k was observed with increasing extractant concentration and lactate and acetate concentrations over time. Using a 1M reactive extractant mix and 1.25 and 12 g/L of solute concentrations, the maximum E % of acetate and lactate were 38.66% and 61.8% in 10 min. The results could contribute to developing a rapid in-situ product recovery system integrated with food waste acidogenesis for lactate and acetate recovery, contributing to the bio-economy.

20.
Environ Sci Pollut Res Int ; 30(32): 78537-78553, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37271787

RESUMO

It is well-documented that accumulation of pharmaceutically active compounds (PhACs), such as antibiotics, in aquatic ecosystems is a prominent environmental hazard. Herein, a series of 2D materials-based heterojunctions, conceptualized based on the integration of graphitic carbon nitride (g-C3N4) with tungsten disulfide (WS2), was fabricated through a facile one-step calcination process, and systematically evaluated for eliminating tetracycline (TC) and sulfamethoxazole (SMX) from aqueous matrices. The microstructure, optical properties, and surface chemistry of the as-prepared composites were examined with a range of microscopy and spectroscopy techniques. In comparison with pristine g-C3N4 or bare WS2, the g-C3N4/WS2 material, with optimal WS2 loading, showed significantly improved photocatalytic activity, towards degradation of TC (84%) and SMX (96%), under visible light. Free radical scavenging experiments revealed that superoxide anions and hydroxyl radicals were predominantly responsible for the rapid breakdown of the PhACs. In addition, the dissociation intermediates and residues were identified and the plausible photocatalytic degradation pathways of TC and SMX over the as-constructed 2D/2D heterojunction were discussed. Further, the photocatalysis end products were non-toxic, as inferred via the resazurin cell viability assay, employing Escherichia coli as a model organism. Most importantly, the 2D/2D g-C3N4/WS2 architecture was structurally resilient and exhibited a fairly stable cycling performance for persistent usage in wastewater treatment. The outcomes of this study testify that 2D/2D heterojunction of g-C3N4 fragments and WS2 nanosheets holds great promise for destroying antibiotics or their metabolites, usually present in wastewaters.


Assuntos
Poluentes Ambientais , Ecossistema , Catálise , Antibacterianos/química , Tetraciclina , Sulfametoxazol , Luz , Preparações Farmacêuticas
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